What's new
  • As of today ICMag has his own Discord server. In this Discord server you can chat, talk with eachother, listen to music, share stories and pictures...and much more. Join now and let's grow together! Join ICMag Discord here! More details in this thread here: here.

How to best control temps in a 12'x12' with 4-5kw bloom and just one exhaust fan?

Zarezhu

Member
Hey guys,
been digging a trench all week, getting a 30a 240v breaker and 20a 120v breaker ran to the shed out back asap (my vegging plants are far too big for the light they're under currently).

As I need the largest portion of my money to build a large fence and purchase a large amount of soil for my outdoor post haste, I'm attempting to make this indoor run extremely cost effective/cheap. I should be able to harvest mid may, and then focus on the outdoor crop at that point.
------------------------------------------------------------------

My room is 12x12x8, located in a fairly shaded area of my backyard. I will be insulating it with 4x8 1" rugged foam sheets.

This bloom cycle will only be 4 1000w's (and possibly a 600w halide on a mover). At the end of this outdoor season, I will upgrade to a 100a sub panel for this shed so I can double the size of the bloom room, as well as seal, add an AC/dehu/co2, and keep it going!

Currently, I have 11 sativa plants recently transplanted from well rooted 5gals to 10 gallon pots of FFOF. These plants are under a single 1000w halide, theyre ready too bloom, much too crowded in the small cramped space.

I have 4 1000w magnetic ballasts. Saves me from having to buy any new ballasts, although digital ballasts would be really nice. I only have 2 hoods, both 6" air cooled. I do not intend to air cool the lights; the hoods will be hung on yoyos with the glass removed. All I have to purchase is 2 additional hoods, or I may just get cheap wing reflectors. I'm choosing to leave the hoods open because I need to heat this room.

Lights on will be at night in northern california. Temperatures here in April-May average daytime highs from 70 to 80 and lows from 45-55. Obviously 45-55 is much too cold for a daytime period, so I will need the lights to keep it around 75-80. The only way I can do this is slow down the exhaust to help keep some of the heat in the room. I have a few exhaust fans to chose from. The exhaust fan will be mounted at the peak of the room, with 2 or 4 passive intakes at the bottom of the room. The exhaust fan will run 24/7 to keep the co2 in the room replenished and to keep the room from getting TOO hot.
------------------------------------------------------------------
Am I going to be able to maintain okay enough temperatures with just an exhaust fan and a speed controller? I may be able to add a second exhaust fan on a thermostat to kick it when the room gets too hot. I feel with these 2 fans, I should be able to maintain temperature fairly well, right? The strain I'm growing is very capable of handling tough conditions, but I would like to get conditions as good as possible because this strain can REALLY shine when it's in peak health.

I may even be able to add a window ac for when its 85 in may and the plants want cool night time temperatures.
-----------------------------------------------------------------
Electrician/wiring costs - $700
2 more hoods, 2 bulbs - $200
Electricity for bloom cycle - ~$2000
Rigid Foam Insulation- $200

I have a lot of supplies already(fans/timers/etc). I can maybe get a few other things if you guys deem anything necessary, as I DO understand the potential yield of this room can be fairly high, and I would HATE to have this entire crop go to shit for some silly reason (like bugs, lol). I'll update with pictures soon, but its just so darn muddy out back.

Any suggestions? I'm not so much an indoor grower as an outdoor grower, but I feel pretty confident in my abilities after growing so many successful outdoor crops. Help me out here guys! Chew apart my ideas! Anything is helpful.

Here's a shot of the strain I'm working with, from my last years outdoor crop. This plant lasted through 3' of snow last november for over a week without dying. Hardy much? This is my outdoor/water only from last season.
 

Attachments

  • CAM00023.jpg
    CAM00023.jpg
    92.1 KB · Views: 9

RoadRash

Member
I looked in your post for a CFM spec, cubic feet per minute, or a Watt spec.


I recently had a "Honey-Do" project of replacing a bathroom fan for a 7 inch duct.

In the process, I saw an 8 inch fan, and since I knew I'd be using this as an exhaust fan for one of my own grow-rooms (air is blown through the wall from the bedroom into the bathroom), I wanted a Really Good Fan.

That 8 inch was about $80, and it was a beauty. :woohoo:

As it turned out, I got by by merely replacing the old standard fan motor on the 7 inch.


But I REALLY liked that 8 inch fan. I don't have the model & part number handy. If you want I can dig it up.


Once I had a 235 watt, 9 inch diameter fan on my desk. It fell off, and I tried to catch it, as if I was practicing my Kung Fu or something. Yes, I was stoned.

OK, so, it was definitely an example of stoned thinking. The blade sliced right down the middle of my index finger to the bone, THOK !

I realized I was going to faint so I went and laid down for a half hour.


Long story short, you can definitely clear the room with one fan.


There is another issue, airflow through the room. It is different if you have 4 small fans in the 4 upper (or lower) corners.


If you are using CO2 supplementation, I guess there's some argument for increasing the airflow at night, when you don't want the CO2 for the plant. That relates to the temperature of the incoming air.
 

Latest posts

Latest posts

Top